Blue coloring-matter.



sist of a mixture of coloring-matters.

UNITED STATES Patented September 22, 1903.

* ATENT FFICE.

RENE BOHN, OF MANNHEIM, GERMANY, ASSIGNOR TO BADISOIIE ANILIN AND SODA FABRIK, OF LUDWVIGSHAFEN-ON-THE-RHINE, GERMANY, A

CORPORATION.

SPECIFICATION forming part cf Letters Patent No. 739,579, dated. September 22, 1903. Application filed July 9, 1902. Serial No. 114,927. (No specimens.)

To all whom, it may concern:

Be it known that I, RENE BOHN, doctor of philosophy and chemist, a citizen of the Swiss Republic, residing at Mannheim, in the Grand Duchy of Baden, Germany, have invented new and useful Improvements in Blue Coloring-Matter, of which the following is a specification.

Beta-amido-anthraquinone on being fused at a suitable temperature with caustic alkali or with caustic alkali and a suitable oxidiz ing agent or on being suitably oxidized in acid solution yields a blue coloring-matter, which may be practically pure 'or may con The said blue coloringmatter results, for instance, on fusing one part of beta-amido-anthraquinone with five parts of caustic potash for half an hour at a temperature of 250 centigrade, pouring the melt into water, blowing air through the solution obtained, collecting 'by filtration the precipitate which separates out and washing well, or by fusing one part of beta-amido-anthraquinone with from two to five parts of caustic potash and one-fifth part of potassium nitrate and proceeding as aforesaid. To purify the coloringmatter, take so much of the well-washed paste as corresponds to ten parts of the dry product, mix it with one thousand parts of water and warm the mixture to about 60 to 70 centigrade. Add thereto twenty parts of caustic-soda lye (containing about twenty-four percent. of NaOH) and one hundred and fifty parts of sodium hydrosultite solution (containing five to six per cent. of the salt) and maintain the temperature at from 60 to 70 centigrade for about one hour or until the coloring-matter is completely dissolved. When this stage is reached, cool the solution and allow it to stand for several hours. The sodium salt of the hydro or soluble form separates out. 001- lect it by filtration, remove the paste from the filter, boil it with water, filter again, and wash well till free from alkali and dry. I will refer to this coloring-matter so obtained as the beta-amido-anthraquinone coloringmatter. The said beta-amido-anthraquinone coloring-matter in the hydro or reduced form dyes unmordanted cotton blue shades of great beauty and fastness, the said shades, however, becoming greenish when treated for one to two minutes at a temperature of about to centigrade with a dilute solution of sodium hypochlorite the strength of which is equivalent to one-eighth to one-fourth per cent. of active chlorin;

I have discovered a derivative of the aforesaid beta-amido-anthraquinone coloring-matter which is distinguished from the parent material and from all other coloring-matters by the fact that in the form of its hydro compound. it dyes unmordantedcotton blue shades, which shades on development by exposure to theair for a sufficient length of time, followed by treatment at a temperature of 15 centigrade for about ten minutes with a dilute solution of sodium hypoclilorite thestrength of which is equivalent to one-fourth per cent. of active chlorin, remain practically unchanged. I obtain my said derivative by treating the betaamido-anthraquinone coloring-matter with chlorin' or bromin or witha body or mixture of bodies which generates such halogens.

My new coloring-matter is practically insoluble in water and is more easily soluble in nitrobenzene than is the parent beta-amidoauthraquinone coloring-matter. On reducing the new derivative with a suitable reducing agent s ay sodium hydrosulfite and caustic soda at a temperature of to ce'ntigrade-it yields a soluble hydro compound with the aforementioned properties.

The following example willserve to further illustrate the nature of this invention and the manner in which the same may be carried into practical edect; but the invention is not confined to the example. The parts are by weight:

Example: Dissolve in two hundred (200) parts of concentrated sulfuric acid (containing ninety-six per cent. of H ten (10) tion the coloring-matter which separates out. In place of sulfuric acid any other suitable solvent can be employed, and in place of bromin the corresponding quantity of chlorin can be used. On treating one (1) part in paste form of the coloring-matter thus obtained, which is suspended in five hundred to one thousand (500 to 1,000) parts of water at a temperature of from fifty to sixty degrees, (50 to 60 centigrade,) with twenty to thirty (20 to 30) parts of a sodium hydrosulfite solution containing about ten (10) per cent. of Na S O and from ten to fifteen (10 to 15) parts of caustic-soda lye containing about twenty-four (24) per cent. NaOI-I the coloringmatter will dissolve in the form of its hydro compound and dye cotton as aforesaid.

What I claim is The coloring-matter such as can be ob- RENE BOHN.

Witnesses:

JOHN L. VHEINKE,

JACOB ADRIAN. 

